One person has been shot dead in Quebec and another wounded after a gunman entered the venue where Pauline Marois, the separatist Parti Quebecois leader who had just become the Canadian province's premier-elect, was giving her victory speech.

Voters in the French-speaking province on Tuesday ousted the governing Liberals and installed the Parti Quebecois as a minority government – in the process making Marois the first female premier of Quebec.

Around midnight, two bodyguards abruptly interrupted Marois's victory speech, bundling her into the backstage area after a deafening boom rang out.

According to Montreal police, one 45-year-old man was fatally shot and a 30-year-old man was in critical condition after a man in his 50s entered the back door of Montreal's Metropolis concert hall, and shot them. He also started a fire on the premises. A spokesman for the force added that another man was being treated in hospital for "nervous shock".

As he was detained, the gunman, wearing a balaclava and a bathrobe, allegedly repeated twice in French with an English accent: "The Anglophones are waking up," an apparent reference to the "maple spring" of student protests against the government that contributed to the snap election being called.

Marois came back on stage to give a final thank-you to her supporters before urging them to calmly evacuate the concert hall.

In a statement issued early on Wednesday, Marois said her thoughts were with the family of the victim. "Following this tragedy all Quebecois are mourning today before such a gratuitous act of violence," she said. "Never will a society such as ours let violence dictate its collective choices."

The Canadian prime minister, Stephen Harper, said in a statement that he was "angered and saddened" by the shooting. "It is a tragic day where an exercise of democracy is met with an act of violence," Harper said. "This atrocious act will not be tolerated and such violence has no place in Canada."

Before the dramatic interruption, Marois reaffirmed her party's commitment to Quebec breaking away from Canada. "As a nation we want to take decisions that concern us on our own," she said. "The future of Quebec is to become a sovereign country."

She highlighted the French language as essential to the future of the province, then addressed anglophone people of Quebec in English, promising to protect them and to forge a shared future together, as well as with first nations.

"Cynicism lost and hope won. For the first time the government of Quebec will be led by a woman." She promised to govern responsibly in the public interest, putting Quebec's divisions aside in favour of common loyalty to the province.

The PQ is likely to form a minority government after winning fewer seats than required to take power outright, and the result leaves questions over whether it will be able to hold a referendum on leaving the Canadian federation.

The snap election was called after a student strike over raising tuition fees and the Liberal government's crackdown on student protesters caused unrest across the province.

Former student strike leader Leo Bureau-Blouin, 20, was elected in his district of Laval for the PQ, making him the youngest elected to the national assembly.

Jean Charest, the leader of the federalist Liberal party, which has governed Quebec for the past nine years, was unseated in his own district of Sherbrook, while his party came in second behind the Parti Quebecois.

Support for the party leader has waned due to his handling of the student strike, allegations of corruption in the construction industry and passage of Bill 78 – a widely condemned anti-protest law that brought hundreds of thousands of Quebecois on to the streets during the spring.

Marois has promised a tuition freeze until a summit on higher education financing is held, has pledged to repeal Bill 78, and would like to pass a third referendum on Quebec sovereignty.

Quebec separating from Canada is a bitterly contentious issue between in the French-speaking province and the election of the PQ only to minority government may indicate Quebec people are not ready to face a third referendum, the previous two having been defeated.

Marois proposes to expand Quebec's language Law 101 preventing francophones and immigrants from attending English junior colleges and has proposed a law that would prevent non-French speakers from running for office.

More controversially, she proposed a secularism charter banning public service employees from wearing overt religious symbols, like the Jewish yarmulke and the Muslim hijab.

Shadak Islam, a digital technician who moved to Quebec from Bangladesh with his wife eight years ago, said it was the PQ's policy on religion that made him vote Liberal. "The headscarf is not a symbol, it's a duty to my religion," he said.

Fear of a referendum could explain why anglophones and immigrants in the province opted for Charest's Liberal party or voted for the upstart Coalition Avenir Quebec (CAQ), the nine-month-old party of former PQ cabinet minister, Francois Legault, who came in third with 19 seats. Legault proposes strengthening the laws that protect the French language, supports a more moderate student tuition rise while promising a decade-long moratorium on any sovereignty referendum.

In fourth place, the two co-leaders of progressive left party Quebec Solidaire, Amir Khadir and Francoise David, were elected in two Montreal districts. The two leaders of the pro-sovereignty party have been in the streets supporting the student strike from the beginning, propose to abolish higher education tuition fees and have a green, pro-feminist, pro-minority platform.

Francoise David, who gained a high profile for having won the campaign debates, said her party would support Marois's PQ on a case-by-case basis, but their two seats won't swing the balance of power to form a pro-sovereignty majority government.

Charest, the ousted Liberal premier, told supporters he accepted responsibility for the defeat. In a riposte to separatism he declared: "The future of Quebec is in Canada."